* [PATCH nf] netfilter: nft_socket: only do sk lookup when indev is available
@ 2022-04-27 16:02 Florian Westphal
2022-04-27 18:10 ` Topi Miettinen
0 siblings, 1 reply; 2+ messages in thread
From: Florian Westphal @ 2022-04-27 16:02 UTC (permalink / raw)
To: netfilter-devel; +Cc: Florian Westphal, Topi Miettinen
nft_socket lacks .validate hooks to restrict its use to the prerouting
and input chains.
Adding such restriction now may break existing setups, also, if skb
has a socket attached to it, nft_socket will work fine.
Therefore, check if the incoming interface is available and NFT_BREAK
in case neither skb->sk nor input device are set.
Reported-by: Topi Miettinen <toiwoton@gmail.com>
Fixes: 554ced0a6e29 ("netfilter: nf_tables: add support for native socket matching")
Signed-off-by: Florian Westphal <fw@strlen.de>
---
net/netfilter/nft_socket.c | 41 +++++++++++++++++++++++++-------------
1 file changed, 27 insertions(+), 14 deletions(-)
diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
index 6d9e8e0a3a7d..cbd1e4523ace 100644
--- a/net/netfilter/nft_socket.c
+++ b/net/netfilter/nft_socket.c
@@ -54,6 +54,32 @@ nft_sock_get_eval_cgroupv2(u32 *dest, struct sock *sk, const struct nft_pktinfo
}
#endif
+static struct sock *nft_socket_do_lookup(const struct nft_pktinfo *pkt)
+{
+ const struct net_device *indev = nft_in(pkt);
+ const struct sk_buff *skb = pkt->skb;
+ struct sock *sk = NULL;
+
+ if (!indev)
+ return NULL;
+
+ switch(nft_pf(pkt)) {
+ case NFPROTO_IPV4:
+ sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, indev);
+ break;
+#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
+ case NFPROTO_IPV6:
+ sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, indev);
+ break;
+#endif
+ default:
+ WARN_ON_ONCE(1);
+ break;
+ }
+
+ return sk;
+}
+
static void nft_socket_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
@@ -67,20 +93,7 @@ static void nft_socket_eval(const struct nft_expr *expr,
sk = NULL;
if (!sk)
- switch(nft_pf(pkt)) {
- case NFPROTO_IPV4:
- sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, nft_in(pkt));
- break;
-#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
- case NFPROTO_IPV6:
- sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, nft_in(pkt));
- break;
-#endif
- default:
- WARN_ON_ONCE(1);
- regs->verdict.code = NFT_BREAK;
- return;
- }
+ sk = nft_socket_do_lookup(pkt);
if (!sk) {
regs->verdict.code = NFT_BREAK;
--
2.35.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH nf] netfilter: nft_socket: only do sk lookup when indev is available
2022-04-27 16:02 [PATCH nf] netfilter: nft_socket: only do sk lookup when indev is available Florian Westphal
@ 2022-04-27 18:10 ` Topi Miettinen
0 siblings, 0 replies; 2+ messages in thread
From: Topi Miettinen @ 2022-04-27 18:10 UTC (permalink / raw)
To: Florian Westphal, netfilter-devel
On 27.4.2022 19.02, Florian Westphal wrote:
> nft_socket lacks .validate hooks to restrict its use to the prerouting
> and input chains.
>
> Adding such restriction now may break existing setups, also, if skb
> has a socket attached to it, nft_socket will work fine.
>
> Therefore, check if the incoming interface is available and NFT_BREAK
> in case neither skb->sk nor input device are set.
>
> Reported-by: Topi Miettinen <toiwoton@gmail.com>
> Fixes: 554ced0a6e29 ("netfilter: nf_tables: add support for native socket matching")
> Signed-off-by: Florian Westphal <fw@strlen.de>
Thanks. After applying this patch, my test case which triggered a BUG in
a few tries, doesn't do it anymore with 25 attempts.
Tested-by: Topi Miettinen <toiwoton@gmail.com>
> ---
> net/netfilter/nft_socket.c | 41 +++++++++++++++++++++++++-------------
> 1 file changed, 27 insertions(+), 14 deletions(-)
>
> diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
> index 6d9e8e0a3a7d..cbd1e4523ace 100644
> --- a/net/netfilter/nft_socket.c
> +++ b/net/netfilter/nft_socket.c
> @@ -54,6 +54,32 @@ nft_sock_get_eval_cgroupv2(u32 *dest, struct sock *sk, const struct nft_pktinfo
> }
> #endif
>
> +static struct sock *nft_socket_do_lookup(const struct nft_pktinfo *pkt)
> +{
> + const struct net_device *indev = nft_in(pkt);
> + const struct sk_buff *skb = pkt->skb;
> + struct sock *sk = NULL;
> +
> + if (!indev)
> + return NULL;
> +
> + switch(nft_pf(pkt)) {
> + case NFPROTO_IPV4:
> + sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, indev);
> + break;
> +#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
> + case NFPROTO_IPV6:
> + sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, indev);
> + break;
> +#endif
> + default:
> + WARN_ON_ONCE(1);
> + break;
> + }
> +
> + return sk;
> +}
> +
> static void nft_socket_eval(const struct nft_expr *expr,
> struct nft_regs *regs,
> const struct nft_pktinfo *pkt)
> @@ -67,20 +93,7 @@ static void nft_socket_eval(const struct nft_expr *expr,
> sk = NULL;
>
> if (!sk)
> - switch(nft_pf(pkt)) {
> - case NFPROTO_IPV4:
> - sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, nft_in(pkt));
> - break;
> -#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
> - case NFPROTO_IPV6:
> - sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, nft_in(pkt));
> - break;
> -#endif
> - default:
> - WARN_ON_ONCE(1);
> - regs->verdict.code = NFT_BREAK;
> - return;
> - }
> + sk = nft_socket_do_lookup(pkt);
>
> if (!sk) {
> regs->verdict.code = NFT_BREAK;
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-04-27 16:02 [PATCH nf] netfilter: nft_socket: only do sk lookup when indev is available Florian Westphal
2022-04-27 18:10 ` Topi Miettinen
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